In an existing touch sensing system, as shown in FIG. 1, touch electrodes 20 are arranged in a matrix, and each of the touch electrodes 20 is connected with a touch driving integrated circuit 50 through a touch signal line 40. In detecting a touch, all the touch electrodes 20 operate in the same way. During the touch detection, touch driving signals generated by the touch driving integrated circuit 50 are supplied to the touch electrodes 20 through the touch signal lines 40 so that a certain number of charges are accumulated on each of the touch electrodes 20, and then a change of the charges on the touch electrode 20 is detected by the touch driving integrated circuit 50 via the touch signal lines 40, so that it is possible to determine which touch electrode(s) 20 is touched and further locate the position of the touch. The touch driving signals and the change of the charges can each be represented as a pulse signal. As shown in FIG. 2, during the touch detection, the touch driving integrated circuit 50 transmits pulse signals to the touch electrodes 20 via the touch signal lines 40, and receives pulse signal from the touch electrodes 20 via these touch signal lines 40 to determine the position of the touch.
In order to reduce a capacitance between two adjacent touch electrodes 20, each touch electrode 20 is arranged in a conductive grid (i.e. a conductive lattice) 301, and all the conductive grids 301 constitute together a whole conductive network unit 30, that is, conductors are placed in space between the touch electrodes 20 arranged in the matrix, to reduce the coupling capacitance between adjacent touch electrodes 20, and hence increase the speed of the touch detection. The conductive network unit 30 is electrically connected to the touch driving integrated circuit 50 and applied with a constant voltage by the touch driving integrated circuit 50, where the constant voltage is used as a common voltage to sustain the stability of the picture displayed in a display phase.
However, the voltage of the conductive network unit 30 is unstable due to the coupling disturbance between the touch electrodes 20 and the conductive network unit 30, thus the luminance at areas corresponding to the touch electrodes 20 is different from that at areas corresponding to the conductive network unit 30 during the display phase, therefore, a shadow caused by the profile of the conductive network unit 30 is likely present in the displayed image, and the shadow is particularly significant in a flickering picture.